The younger son of Seleucus
II succeeded his assassinated brother, Seleucus
III in 223 BCE.
Though barely 19, he immediately set out to regain the territory that his
father & brother had lost. By a show of force & skillful
diplomacy he formed alliances with neighboring rulers from Pergamum to
northern India, often allowing opponents to retain their thrones in
exchange for tribute. By 205 BCE
he had formed such an extensive system of vassal kingdoms to the East that
he adopted the ancient Persian title of "the great
king" & promoted a royal cult in which he was worshipped as
a god. His Greek subjects compared him to Alexander the Great.

Turning his attention to
western territories he formed an alliance with Philip
V of Macedon against
Ptolemy V of Egypt. In 200 BCE
he defeated the Egyptian forces at Panias
(Lebanon) and claimed control of Palestine & Phoenicia. The Jewish
temple state of Jerusalem
was granted special privileges for recognizing his suzerainty. Pressing
his military advantage, Antiochus invaded Egypt itself, forcing a peace
treaty (195 BCE)
that finally formalized Ptolemaic recognition of Seleucid control of Syria
& Palestine, territory that had been claimed by Seleucus
I a century earlier.

But Antiochus did not rest on
that victory. When Philip was defeated by the Romans, Antiochus led his
forces to regain the cities of western Asia minor that his father had
lost. Not content with having extended Seleucid control over more
territory than any of his predecessors, he defied Roman warnings by
crossing into Europe. Conflict with Rome became unavoidable when
Antiochus gave refuge to Hannibal of Carthage & made him his military
advisor. He was routed by the Romans & their allies at
Thermopylae in Greece & Magnesia, Asia Minor (191-190 BCE).
To conclude a peace treaty he had to abandon western Asia Minor &
allow his youngest son, (who later ruled as Antiochus IV), to be taken to
Rome as a hostage.

He was killed at a temple of Ba'al in Susa
a few years later, while exacting tribute to replenish the depleted royal
treasury.

Surprisingly the
royal cult sponsored by Antiochus III is not reflected in any of the
currency he issued. Instead
his coins minted at Antioch bore traditional Seleucid iconography. The
face of the silver tetradrachma at the left above bears the diademed
king's likeness. The
reverse side (center) portrays Apollo with bow &
arrow seated on a phallic stone with the same simple inscription, Basileos
Antiochou ("of
King Antiochus"), used by predecessors with the same name [cf. Antriochus
I & Antiochus
II]. Instead of the Greek mythological imagery, however, Antiochus
III's coins minted in less Hellenized regions used traditional local
symbols on their reverse side. Those made in eastern provinces like
Nisibis (Assyria) portrayed an elephant (right), while those minted in western Semitic centers
like Tyre (Phoenicia) featured a date palm (not shown).